Outcome 5-6 - notes Light & Color.doc

(1)

III. Outcomes 5 to 6 – Light (aka Electromagnetic Waves) (Video: ..\Waves Video.asx - 9:08-12:10)

A) Electromagnetic Waves – Waves of oscillating electric and magnetic fields that move at the speed of light.

-- Anything that creates oscillating magnetic OR electric fields will create electromagnetic waves.

B) Light – All forms of electromagnetic waves.

Examples: Visible, ultraviolet, infrared, radio, etc. . . .

--> Speed of Light is an important constant in physics and is given the symbol “c.”

as in: E= mc2

--> Light does this:

1) Travels fast (3 x 108_{m/s = 300,000,000 m/s) and over}

long distances.

2) Travels in a straight line.

3) Carries energy, color and information.

4) Changes when it interacts with matter (atoms). C) Electromagnetic spectrum – A listing of all the

wavelengths/frequencies of electromagnetic waves.

-- Uses of Various forms:

1) Radio – Radio, TV, Radar sending and receiving. 2) Microwaves – Cell phones, Micowave Ovens, most

satellite communication.

3) Infrared – heat, remote controls, guided missiles, “night” vision goggles.

4) Ultraviolet (UVA, UVB, UVC)– black lights, kill germs, fluorescent light bulbs, laser engravers, skin cancer (UVB).

5) X-rays – x-ray images, radiation therapy to fight cancer.

6) Gamma rays – kill germs, radiation therapy, nuclear medicine to fight cancer.

D) Light has dual properties – which means it behaves in two ways…

1) …. like a particle called a photon and like a wave.

Photon – A massless bundle of light energy. Smallest quantity of light.

(2)

2) Light with high energy photons (gamma, x-rays, U.V.) act more like particle.

3) Light with low energy photons (radio, infrared, visible) act more like waves.

E) When light strikes any form of matter the light will be: transmitted, absorbed, reflected or a combination of these.

1) transmitted – energy passes through.

-- During light transmission these can happen:

a) dispersion – white light refracting into its colors b) refraction – bending of light rays.

c) polarization – light’s electric fields are lineup. 2) absorbed,

3) reflected OR

4) any combination of these (i.e.: Blue shirts reflect blue and absorb all other colors, scattering of light).

-->

So if the matter is . . .

1) Transparent – Light is transmitted through the object or medium w/out scattering the light.

Examples: Clear water, glass, air, an overhead sheet 2) Translucent – Light is transmitted but with no detail and

a great deal of scattering.

Examples: Frosted glass, light covers

3) Opaque – Light is absorbed and/or reflected but is NOT transmitted.

Examples: Desk tops, clothing, walls, mirrors F) Red Shift of Light – The Doppler Effect for light.

Light from objects (like galaxies or stars out of our Galaxy) that are moving away from us, “shifts” toward the red part of the spectrum.

(RED SHIFTVideo: ..\Waves Video.asx - 15:15-16:12)

G) Light interaction with curved surfaces. 1) Concave surfaces.

a) Concave lenses – Refraction causes light to diverge (separate) as it passes through.

b) Concave mirrors – Reflection causes light to converge (come together) after it reflects.

(3)

a) Convex lenses – Refraction causes light to converge as it passes through.

b) Convex mirrors – Reflection causes light to diverge after it reflects.

H) Colors of Light

1) Additive Primary Colors of Light – BLUE, RED, GREEN – The three colors of light that when combined can make any color.

When combined equally = white.

2) Secondary Colors of Light – CYANCYAN, MAGENTAMAGENTA, YELLOWYELLOW– Colors of light that come from the combining of two Primary Colors.

3) Complimentary Colors of Light – Two colors of light combined that will make white. Must be one primary and its secondary partner.

BLUE +YELLOW YELLOW

RED + CYAN CYAN

GREEN + MAGENTA MAGENTA

4) Subtractive Primary Colors (aka Pigments) – CYANCYAN,

MAGENTA

MAGENTA, YELLOWYELLOW - when combined equally = black. Mixed to absorb (which subtracts light) and reflect light.

Primary, Secondary, Complimentary, Pigments: Colors.ppt

(4)

IV. Outcomes 6 to 9 – Light

(aka Electromagnetic Waves)

(Video: ..\Waves Video.asx - 9:08-12:10)

Electromagnetic spectrum Intro’ (5:20):

http://www.youtube.com/watch? v=cfXzwh3KadE

Bil Nye Light & Color (6:00): http://www.youtube.com/watch? v=gtgBHsSzCPE

A)

Electromagnetic Waves

– Waves of

oscillating

electric and magnetic

(5)

-- Anything that creates oscillating

magnetic

OR

electric

fields will

(6)

-- Anything that creates oscillating magnetic OR electric fields will create electromagnetic waves.

B) Light –

All forms of

electro

magnetic

waves

.

(7)

B) Light – All forms of electromagnetic energy.

-->

Speed of Light

is an important

constant

in physics and is given

the symbol

“c.”

As in: E =

(8)

--> Speed of Light is an important constant in physics and is given the symbol “c.”

--> Light does this:

1) Travels

fast

(3 x 10

8

_{m/s =}

300,000,000

m/s or

669,000,000

mph

) and over

long distances

.

2) Travels in a

straight line

.

(9)

-- Light does this:

1) Travels fast and over long distances. 2) Travels in a straight line.

3) Carries

energy

,

color

and

information

.

4) Changes when it

interacts with

(10)

4) Changes when it interacts with matter (atoms).

C) Electromagnetic spectrum –

A listing of all the

wavelengths or

frequencies

of electromagnetic

waves.

(11)

(12)

1) Radio –

Radio stations, TV,

Radar sending and receiving.

(13)

1) Radio – Radio, TV, Radar sending and receiving.

2) Microwaves –

Cell phones,

Microwave Ovens, most satellite

communication

.

(14)

1) Radio – Radio, TV, Radar sending and receiving.

2) Microwaves – Cell phones, Microwave Ovens, most satellite communication.

3) Infrared –

heat, TV & stereo

remote controls, guided missiles,

“night” vision goggles

.

(15)

2) Microwaves – Cell phones, Microwave Ovens, most satellite communication.

4) Ultraviolet (UVA, UVB, UVC)–

black lights, kill germs,

fluorescent light bulbs,

laser engravers, skin cancer

(UVB).

(16)

4) Ultraviolet (UVA, UVB, UVC)– black lights, kill germs, fluorescent light bulbs, laser engravers, skin cancer (UVB).

5) X-rays –

x-ray images,

radiation therapy to fight cancer

.

(17)

4) Ultraviolet (UVA, UVB, UVC)– black lights, kill germs, fluorescent light bulbs, laser engravers, skin cancer (UVB).

6) Gamma rays –

kill germs,

radiation therapy,

(18)

6) Gamma rays – kill germs, radiation therapy, nuclear medicine to fight cancer.

(19)

D) Light has dual properties – which means it behaves in two ways…

1) …. like a particle called a

photon

and like a

wave

.

Light

diffraction

tells us that light has wave

properties.

The

Photoelectric Effect

tells us that light has

particle properties.

photon

Light Energy Electrons are tossed out

(20)

F) Light has dual properties – which means it behaves in two ways…

1) …. like a particle called a photon and like a wave

Photon

– A massless bundle of

light

(21)

1) …. like a particle called a photon and like a wave Photon – A massless bundle of light energy. Smallest

quantity of light.

2) Light with

high energy photons

(gamma, x-rays, U.V.) act more

like

particles

.

-- Have enough energy to knock

electrons off of atoms and break

bonds between atoms.

3) Light with

low energy photons

(22)

2) Light with high energy photons (gamma, x-rays, U.V.) act more like particles.

3) Light with low energy photons (radio, infrared, visible) act more like waves.

E) When light strikes any form of

matter the light will be:

transmitted

,

absorbed

,

reflected

, or a

(23)

1) transmitted –

energy passes

(24)

-- During light transmission these can

happen:

a)

dispersion

–

(25)

-- During light transmission these can happen:

a) dispersion – white light

refracting

into its

colors

.

(26)

a) dispersion – white light refracting into its colors b) refraction – bending of light rays.

c) polarization – light’s

electric fields

(27)

(28)

c) polarization – light’s electric fields are lineup.

2)

absorbed

,

3)

reflected

OR

4) any

combination of these

(29)

2) absorbed, 3) reflected OR

4) any combination of these

Examples: Blue shirts

reflect

blue and

absorb

all other colors, also,

scattering

of light

.

(30)



So if the matter is . . .

1)

Transparent

–

Light is

transmitted

through the

object or medium without

scattering the light

.

(31)



So if the matter is . . .

Examples:

clear water,

(32)

Examples: Clear water, glass, air

2) Translucent –

Light is

transmitted

but with

no detail

and a great deal of

scattering

.

(33)

2) Translucent – Light is transmitted but with no detail and a great deal of scattering.

Examples:

(34)

2) Translucent – Light is transmitted but with no detail and a great deal of scattering.

3)

Opaque

–

Light is

absorbed

and/or

reflected

(35)

3) Opaque – Light is absorbed and/or reflected but is NOT transmitted.

Examples:

Desk tops,

clothing

,

walls,

(36)

F) Red Shift of Light – The

Doppler Effect

for light.

Doppler Effect and Red Shift [starts @ 1:20] (2:45):

http://www.youtube.com/watch?v=y5tKC3nEx2I

(37)

H) Red Shift of Light – The Doppler Effect for light.

Light from objects (like other

galaxies

or

stars

out of our

Galaxy) that are

moving

away

from us, “shifts”

(38)

(39)

G) Light interaction with curved

surfaces.

1) Concave surfaces.

(40)

I) Light interaction with curved surfaces. 1) Concave surfaces.

a) Concave lenses –

Refraction

causes light to

diverge

(41)

a) Concave lenses – Refraction causes light to diverge (separate) as it passes through.

b) Concave mirrors –

Reflection

causes light to

converge

(42)

b) Concave mirrors – Reflection causes light to converge (come together) after it reflects.

2) Convex surfaces.

(43)

2) Convex surfaces.

a) Convex lenses –

Refraction

(44)

a) Convex lenses – Refraction causes light to converge as it passes through.

b) Convex mirrors –

Reflection

(45)

b) Convex mirrors – Reflection causes light to diverge after it reflects.

H) Colors of Light

(46)

RED

GREEN

BLUE

Primary

J) Colors of Light

1) Primary Colors of Light – BLUE, RED, GREEN –

The

three colors of light that

when combined can make

any color

.

+

When combined

(47)

1) Primary Colors of Light – BLUE, RED, GREEN – The three colors of light that when combined can make any color. When combined equally = white.

2) Secondary Colors of Light

–

CYAN

,

MAGENTA

,

YELLOW

(48)

RED

GREEN

BLUE

YELLOW

MAGENTA

CYAN

Primary

When combined equally = white.

2) Secondary Colors of Light – CYANCYAN, MAGENTAMAGENTA, YELLOWYELLOW–

Colors of light that come

from the combining of

two

Primary Colors

.

(49)

3) Complimentary Colors of

Light –

Two colors of light combined

(50)

3) Complimentary Colors of Light –

Two colors of

light combined that will make white.

Must be

one primary

and its

(51)

3) Complimentary Colors of Light – Two colors of light combined that will make white. Must be one primary and its secondary partner.